1. Field of the Invention
The present invention relates to an image pick-up apparatus, an exposure controlling method, and a computer program, and more particularly to an image pick-up apparatus which is capable of setting a suitable exposure correction value, an exposure controlling method, and a computer program.
2. Description of the Related Art
A recent digital camera can take a photograph of an image of a subject even in various environments with proper exposure by using an automatic exposure correcting function. That is to say, the recent digital camera has a construction with which brightness is automatically detected, proper exposure is determined in accordance with the detected information, and an image of a subject is photographed with the exposure thus determined, thereby enabling the image of the subject suitable for the current brightness to be photographed.
However, the suitable exposure correction may not be performed with the automatic exposure according function under all the environments. That is to say, the brightness measured with the digital camera may not correspond to the brightness of the objective subject depending on a relationship between the objective subject and a light radiation direction. In such a case, the image photographed based on the automatic exposure correction may be different from an image which a user intends to obtain. In addition, the user wants to adjust the exposure in accordance with his/her taste without using the automatic exposure correcting function in some cases.
Many digital cameras have a function of adjusting the exposure with the automatic exposure correcting function being released by a manual manipulation made by the user. When the user manually corrects the exposure, in many digital cameras, for example, auxiliary information is presented to a display portion of the digital camera, and the user manipulates a manipulation portion based on the auxiliary information, thereby adjusting the exposure of the digital camera. With regard to the auxiliary information presented to the user, for example, there are histogram display on luminance data, and the like. The user adjusts an exposure correction value (EV value) in accordance with his/her experience and intuition while referring to the auxiliary information, and under this condition, takes a photograph of an image of a subject.
The exposure adjustment is generally carried out as processing for setting the exposure correction value (EV value). For example, the EV value is set which is determined to be suitable from the set range, for the exposure correction value (EV value), of −2.0 EV to 2.0 EV. The user who has experienced the exposure adjustment can readily determine the EV value which should be set in correspondence to the brightness of the photographed environment. However, the general user does not know what degrees of the brightness the EV values are suitable for in many cases. In such cases, the user may not properly carry out the processing for setting the exposure correction value (EV value) suitable for an image of which he/she wants to photograph.
That is to say, there is encountered a problem such that it is difficult for the user who has inexperienced the photographing that the camera is adjusted by himself/herself to carry out the optimal exposure adjustment. For example, even when the histogram on the luminance data is displayed on the display portion of the camera, the user does not understand how to read the displayed data, and also does not understand how to exposure correction is carried out. In addition, when the information, on a numeric value, typified by “an exposure value (EV value) is +2.0” is merely shown, the user may be difficult to image what image will be photographed based on this set value gets.
As a result, when many users utilizing their digital cameras intend to set manually the exposure correction value with the automatic exposure correcting function being released, they may not suitably set the exposure. Thus, there is encountered a problem such that they may not take a photograph of an image of a subject as they wish.
In addition, they fear a failure in photographing based on the manual adjustment, and thus hesitate to manually set the exposure correction value. Thus, there is also caused a problem such that as a result of taking a photograph of an image by using the automatic exposure correcting function, many users may not take a photograph of the image to their satisfaction.